The Infiltration of Evil in the Movie

I didn't really realize there was like a fucking threesome where they're eating a third person. I did not see that. The video log showing what the crew members were doing. People are doing it and killing each other at same time. It's very confusing because it doesn't really give a like an easy explanation as to why an object going to this dimension then comes back with sentience. And it's almost like the ship has some sort of immune system.